Thinking of swapping my 140 heads for 110 set up

[krimepays]

I have a buggy with a 110 block and 140 heads with 4 primary carbs and the rotator kit, I am thinking of just putting some 110 heads on and running either a single or dual carbs. The buggy will honestly not be doing 100mph , but more trail riding in the desert.
Right now I have the 2 secondaries removed and plated off and it seems to have plenty of power for what I need it to do.
will I have to change anything other than the heads and gasket carbs etc..?
What should I ask for my setup if I were going to sell them?
Should I just try and trade for some nice 110 heads and carbs?
Would it be better to just go back to 2 primaries and 2 secondaries?
I really dont like the 4 carb thing, but mainly because its an offroad vehicle that takes a pounding and gets dirty and the carbs have been nothing but a headache!
Any suggestions or advice?

[chris]

I may be wrong, but you are basically running a (slightly modified) 110 as you have it. The main difference between what you have now and the 110 heads would really be the bigger valves and exhaust that you have now, and if it were me, I'd probably want to keep the current set up.

[bbodie52]

I agree with the above assessment.

...I have a buggy with a 110 block and 140 heads...Right now I have the 2 secondaries removed and plated off and it seems to have plenty of power for what I need it to do...Should I just try and trade for some nice 110 heads and carbs...Would it be better to just go back to 2 primaries and 2 secondaries?

I really don't like the 4 carb thing, but mainly because its an off road vehicle that takes a pounding and gets dirty and the carbs have been nothing but a headache!

The 110 hp and 140 hp short blocks are identical — including the camshaft. The combustion chamber volume is the same for the 110 hp and 140 hp heads, so both heads present the same 9.25:1 compression ratio.

With the secondary carburetors already removed, you have essentially a 110 hp configuration with big intake valves and larger exhaust ports. If you were to change the 140 hp heads and substitute 110 hp heads, the performance and driveability of your engine would likely feel just like what you have now.

If for some reason you do decide to obtain a pair of 110 hp heads to install on your engine, make sure they came from a 1965-1969 engine. The 110 hp heads from a 1964 engine will not fit your existing cylinder barrels, unless you have the openings machined from 3-3/4" to 3-13/16".

[azdave]

The 110 hp and 140 hp short blocks are identical — including the camshaft.

Except the 140 came with a nitrided crankshaft.

[bbodie52]

True. I had forgotten about the nitrided crankshafts found in the 140 hp and 180 hp turbocharged engines. It is not a huge difference on a low-revving street engine, or a low-revving low horsepower configuration as anticipated in the application discussed here, and the presence of a harmonic balancer is likely more significant, but it was a production difference found in the top two 164 CI Corvair engines.

Here is a link to a brief discussion on Corvair nitrided crankshafts on the Corvair Center...


http://corvaircenter.com/phorum/read.ph ... 115,249229

As far as I can tell, the correct GM part number for the 140 hp and 180 hp engine was 3856704, but there is no mention of nitriding or any other unique characteristic of that crankshaft in the GM parts catalog. I'm not sure how you would identify the nitrided crankshaft outside of the original source engine.

[bbodie52]

A little research answered my own question...

Nitriding is a case-hardening process in which nitrogen is introduced into the surface of a ferrous alloy such as steel by holding the metal at a temperature below that at which the crystal structure begins to transform to austenite on heating as defined by the Iron-Carbon Phase Diagram.

All of the Corvair turbocharged engines had nitrided crankshafts for added strength. They are identified by an ampersand "&" stamped on the flywheel end of the crankshaft. These nitrided cranks were also used in the 4 carb 140 engines...

viewtopic.php?f=55&t=5204&p=35076&hilit=nitrided#p35076

This ampersand stamp indicating a nitrided crankshaft is also mentioned on page 69 in the book Performance Corvairs: How to Hotrod the Corvair Engine and Chassis by Bill Fisher and Seth Emerson. The book also mentions that GM lab tests showed Spyder model (1962-1963) crankshafts (forged in SAE 5140 chromium alloy steel and surface hardened by nitriding) were five times more resistant to cracking than the plain carbon steel models. In 1964 alloy steel crankshafts were used in place of the previous forged carbon steel in all models as the displacement was increased to 164 cubic inches by raising the stroke from 2.6 inches to 2.94 inches. A harmonic balancer was also used on all engines except the 95 hp unit. As previously mentioned, nitriding was included on the highest horsepower 140 hp and turbocharged engines.


The above book is also now available in a digital Kindle version for only $9.99 or in paperback for $22.47 on Amazon.com.

http://www.amazon.com/Performance-Corva ... 1408727195

http://www.amazon.com/Performance-Corva ... 195&sr=8-1

[krimepays]

Thanks guys, I figured it was pretty much the same thing but have heard the 140 heads like to eat valve seats so my thinking on the 110 heads was more reliability based. So I will just leave it as is. And now I get to replace a flywheel! but it's better than the rod or main bearing I thought it was!
Thanks again for the info!